<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Vue中的动画封装</title>
    <script src="./vue.js"></script>
</head>
<body>

<div id="root">

    <fade :show="show">
        <div>hello world</div>
    </fade>

    <fade :show="show">
        <h1>hello world</h1>
    </fade>

    <button @click="handleBtnClick">toggle</button>
</div>

<script>

    Vue.component('fade', {
        props: ['show'],
        template: `
        <transition @before-enter="handleBeforeEnter" @enter="handleEnter">
          <slot v-if="show"></slot>
        </transition>
      `,

        methods: {
            handleBeforeEnter: function (el) {
                el.style.color = 'red'
            },
            handleEnter: function (el, done) {
                setTimeout(() => {
                    el.style.color = 'green'
                    done()
                }, 2000)
            }
        }
    })

    var vm = new Vue({
        el: "#root",
        data: {
            show: false
        },
        methods: {
            handleBtnClick: function () {
                this.show = !this.show
            }
        }
    })
</script>

</body>
</html>